During the construction of a tunnel it is necessary to attach objects, such as cables, pipes, lighting, traffic signs, etc. to the vault of the tunnel, the surface whereof is generally made of concrete.
A tunnel several kilometers in length can thus require the drilling of several tens of thousands of holes in the vault and walls.
To this end, it is necessary to drill a hole in the vault or wall of the tunnel, and then to insert into it an anchoring element, such as a dowel, allowing the attachment of the object.
At the present time, these operations are carried out by an operator.
Considering the height of the vault (several meters), it is necessary to install a scaffolding so that the operator can be in a suitable position with respect to the intended location. The placement of the hole is marked manually, using chalk for example, then the hole is drilled by the operator by means of a drill. Then, the anchoring element is inserted into the hole.
This intervention by an operator proves unsatisfactory for various reasons.
On the one hand, the drilling of each hole and the installation of each respective anchoring element require considerable time.
On the other hand, the operator is exposed to conditions harmful to his health, such as an atmosphere loaded with dust, a noisy environment, without counting the risks associated with working at a height.
A need has therefore appeared to automate these operations so as to minimize the intervention of an operator.
Attempts at automating the drilling of holes in tunnels have already been described for different applications.
The article entitled “The development and testing of a mobile drilling robot” [1] describes a robot mounted on wheels designed to drill holes in the floor of a tunnel designed to be equipped with a railway. The robot comprises two perforators allowing two holes to be drilled simultaneously, as well as means for controlling the position in two directions (in a horizontal plane formed by the ground) and the orientation of the perforators and a position sensor with rotating lasers using reference reflectors. Based on the coordinates of the holes to be drilled and of the reflectors, the robot is capable of carrying out precision drilling at a high rate.
However, drilling holes into the vault of a tunnel has a greater complexity than into the ground, and imposes in particular controlling the position and orientation of the robot in the three spatial directions. On the other hand, document [1] does not address the problem of automated installation of anchoring elements in the holes.
Document CN 201714390 [2], for its part, describes a robot designed to excavate rocks for the purpose of drilling a tunnel. This robot is designed to cut holes into rocks so as to then place there a stick of explosive to make the rock explode. This document does not address the problem of precise positioning of the hole in the vault of a tunnel already constructed, nor that of installing anchoring elements.